Would be an awesome fight. I'd take Gus but Rumble could do well. Jimi Manuwa tagged Gus solid a couple of times, and I think Rumble has the more diverse striking, and his grappling is also not a weakness like Manuwa's grappling was.
Fan of Sherdogs Most Hated™
Jon "Psychotic Undertone" Jones
Conor "Anti Wrestlefuck" McGregor
Nick "Uneducated Fool" Diaz
Ronda "She's No Angel" Rousey